Encyclopedia recommendations for a bright 10 year old
December 10, 2003 7:44 PM   Subscribe

Where can I find an Encyclopedia of Electricity for a very bright, engineering-oriented ten-year-old? [more inside]

My son's ten, eleven next month, and reads voraciously. He has recently become very interested in electricity and sometimes asks questions I don't have a clue how to answer. Like "if magnetism works because of polarity, what about those the magnets that hold those little words on our refrigerator?" or "do bumper cars work because both the ceiling and the floor are electrified and the car makes the connection between them?" Obviously I could look each of these up on the Internet and eventually get back to him, but I want him to be able to find the answers himself, preferably in one volume (not via the Internet). I'm thinking there must be something geared to an 11- or 12-year-old that would be visually engaging but also pretty complete and well-organized in explaining the workings of electricity (and magnetism, probably). I've looked on amazon and a couple other places and so far there seems to be a wide gulf between 8-year-old-oriented "rub a balloon on your hair"-style fun books and "your complete course in electricity in simple steps" for those with a high-school education. Anybody know of anything more suitable?
posted by soyjoy to Shopping (17 answers total)
You could always print out the contents of How Stuff Works.
posted by PenDevil at 7:51 PM on December 10, 2003

Bill Nye often has interesting stuff.
posted by riffola at 8:21 PM on December 10, 2003

The Way Things Work (and follow up The New Way Things Work are both great.
posted by Yelling At Nothing at 9:09 PM on December 10, 2003

I give 2 thumbs up to The Way Things Work. My dad bought a copy for me and I can seriously say I learned many things from it. Buy it. Seriously.
posted by Keyser Soze at 10:03 PM on December 10, 2003

Is that the book with the mammoths? Amazon doesn't have a cover. If it is, I couldn't recommend it anymore highly.
posted by Orange Goblin at 12:35 AM on December 11, 2003

The tricky thing is that electricity deals with some very abstract ideas that would be difficult to convey with any meaning to children who aren't yet well into high school. Another issue is that electricity is, well, lethal. Maybe there is a pervading feeling that getting children interested in electricity is a bad idea. From this point of view, going with a "how things work" approach rather than an "understanding electricity" approach might be advisable.

However, in answer to the first question, yes, fridge magnets are just the same as other magnets, and polarity applies (try putting the magnets on the fridge the other way round to test this).

In answer to the second question, with bumper cars only the ceiling is electrified. Possibly the easiest way to imagine this is to think of the ceiling as a circuit, and each car as an extension of the circuit, with the current passing both in and out of each car. Just like any electrical appliance in your house, you only need to connect to the circuit in your house, you don't need to connect it between two sources.

If the interest in electrics continues, and he develops an understanding of harmonics, please put him in touch, as they remain a mystery to me.
posted by nthdegx at 5:07 AM on December 11, 2003

Not really answering the question, but you should definitely get him some books about Nikola Tesla. One of the most fascinating characters of the last century - or any century. I think I even once saw a Tesla book geared to kids, though it sounds like your son might be beyond that.
posted by CunningLinguist at 7:06 AM on December 11, 2003

Thanks, all. We have gotten The Way Things Work (the New one) out of the library a couple times, and probably ought to own it, but I'm looking for something with a little more organized information and text relative to the visuals. In web terms, I want more "pull" than "push."

And again, I'm not interested in something that has electrical experiments to do, so I don't know that the lethality is an issue here, though I can see why it would make sense on a broader scale. I just want him to have a reference that he can come back to as he does start understanding electricity better, and find answers to questions that will arise and will be far beyond what I can answer.

Thanks for the bumper car answer, nthdegx - rereading my post, I see I misstated his question. It wasn't whether the floor was electrified, only if it was metal and thus was connecting to the circuit from the ceiling. But your answer clears that up. I did suggest that this was probably the case - ha! - "just as you can plug something into an outlet and the circuit goes through it and back." But when he said, "but with outlets aren't the wires leading to two channels that have a difference in voltage or something?" I said, "well, uh, yeah... sure they... are... I guess... um....ya see, uh...."
posted by soyjoy at 7:38 AM on December 11, 2003

You should consider getting him one of those "150-in-1" electronic projects from Radio Shack. It works from batteries so there is no danger, they come with a decent booklet and he can learn by doing. I had one as a kid (75-in-1, my dad wouldn't go for the 150 one) and loved it. In my experience the concepts of voltage and current are the most misunderstood by 'laypersons' and he could get an idea with this, experimenting with resistors and small light bulbs etc.
posted by golo at 8:56 AM on December 11, 2003

Not electricity specifically, but my family has gotten a ton of use out of the New York Public Library's Science Desk Reference. It's great for factoids and settling the score about those science-related dinner-table bets.

And looking at prior comments, I add my vote to Howstuffworks.
posted by Aaorn at 9:22 AM on December 11, 2003

soyjoy - Hey that's right, the two prongs of a plug do go into channels with a difference in voltage. Since the top of the bumper car connects to a single wire grid ceiling, where does the voltage differential come from to supply power? I just did some googling & didn't find any leads. Forget the kid, now I want to know the answer! Can anyone with an EE background help out?
posted by tdismukes at 9:47 AM on December 11, 2003

OK, I did a little more searching. The current comes into the bumper car from the ceiling (higher voltage). It flows out from the car into the floor (lower voltage). That was bugging me for a couple of minutes.
posted by tdismukes at 9:56 AM on December 11, 2003

Soyjoy: Whatever you do, don't give the child half-digested information from an internet forum. People tend to have a way of stating wrong things with great confidence. (Casts a hairy eyeball at nthdegx.)
posted by ptermit at 12:18 PM on December 11, 2003

Ugh. To provide some redeeming value to my snark, I guess I should provide an explanation now.

An electric circuit is somewhat analogous to flowing water. Water "wants" to flow from a high point (at the top of a waterfall, say) to a low point (at the bottom of a waterfall.) You can use this tendency to do work... turning a waterwheel by intercepting the flowing water, for instance. Electricity "wants" to flow from a high potential (higher voltage) to a low potential (lower voltage). You can use this tendency to do work... turning an electric motor or lighting a lightbulb that you place in the path of the current. [There's some ugliness here having to do with physics conventions vs. reality and AC vs. DC, so don't take these statements *too* literally.]

A bumper car is essentially a motor. The mesh at the ceiling is at a higher voltage than the floor. When the bumper car touches the ceiling and the floor simultaneously, the current flows from the ceiling, through the car's motor, and down to the floor (which is "grounded") and dissipates, making the motor run.

As for magnets, it's a bit more complicated, but the "try putting the magnets on the fridge the other way round to test this" is a red herring. An extremely simplified explanation (again, don't take too literally) is that the atoms in the refrigerator's metal are like tiny, weak bar magnets themselves. These atom-magnets are allowed to spin around in place. When a magnet approaches the metal, the atoms twist so that they are aligned to attract the approaching magnet. This means that it doesn't matter whether the magnet's N or S end is pointing at the fridge, it'll attract just the same, because the atoms will spin around to accommodate. (In fact, many refrigerator magnets, particularly the cheap bendy kinds, have an alternating N/S pattern on their surfaces. Take two of them and stick them together and pull them apart laterally, and you can often feel magnetic "ridges" as the magnets alternately stick and slip.)

Oh, and don't freak out about the lethality of electricity. So long as the kid plays with ordinary batteries of the 9V and less variety and stays away from futzing with electrical outlets, he should be OK putting together simple circuits.
posted by ptermit at 12:42 PM on December 11, 2003

(Clarification... by futzing with electrical outlets, I mean that he shouldn't play around with anything that's plugged into an outlet. Stick to batteries as the power source.)
posted by ptermit at 12:44 PM on December 11, 2003

So my kid was right and I was wrong? The current really does need to go all the way through to the floor? You see why I need to get some kind of book. At least it will keep him distracted - for a while - from the fact that he knows more than his old man...

Thanks for the info, ptermit - and everybody. And thank you, AskMetafilter!
posted by soyjoy at 7:46 AM on December 12, 2003

"The current comes into the bumper car from the ceiling (higher voltage). It flows out from the car into the floor (lower voltage); "try putting the magnets on the fridge the other way round to test this" is a red herring"

Er. My bad. Thanks, ptermit.

Re: the experimentation, I think providing something to play with, with batteries, is a terrific idea. I didn't mean to imply you were hoping he'd stick things into outlets, I just meant that it might be one of the reasons why there aren't resources available for children around that age. It looks a lot like I need to do some experiments of my own, eh?
posted by nthdegx at 9:31 AM on December 12, 2003

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